Orthopedic Coding Alert

"The 'plus' designation identifies those codes that the physician performs in addition to other, usually closely related, procedures or services," says Tara L. Conklin, CPC, an instructor for CRN-Institute, a coding and reimbursement institution offering courses in reimbursement, medical billing, outpatient coding certification and inpatient coding certification. "That's why they are called 'add-on' codes: You cannot report them alone, but always 'add them on' to another procedure or service."
 
Example: A surgeon would never use an operating microscope (69990) in the absence of a surgical procedure that required her to visualize a particular anatomic location. Because you would only bill 69990 in addition to another procedure, CPT lists the code as an add-on.
 
Some E/M services qualify as add-on codes as well. For instance, you may report prolonged services (such as +99354, Prolonged physician service in the office or other outpatient setting requiring direct [fact-to-face] patient contact beyond the usual service [e.g., prolonged care and treatment of an acute asthmatic patient in an outpatient setting]; first hour [list separately in addition to code for office or other outpatient evaluation and management service]; and +99355, ... each additional 30 minutes) only in addition to other, primary E/M services, such as an outpatient visit, consult, etc.
 
Note: For a complete list of add-on codes, consult Appendix D of CPT.

Point 2: List Add-Ons With a Primary Procedure

As noted above, you should never report an add-on code without also listing a "primary" procedure. Rather, the add-on code describes additional intraservice work associated with specific primary procedures the physician performs during the same operative session or patient encounter, says Anita L. Carter, LPN, CPC, an instructor at A+ Medical Management and Education, a school for billing and coding in Absecon, N.J.
 
In most cases, the primary code(s) for a given add-on code immediately precede the add-on code in the CPT listings. For example, consider the following CPT
code sequence:

 

In this case, the add-on code (22522) follows the primary procedure codes (22520 and 22521) to which it is related. And, CPT instructs, "Use 22522 in conjunction with codes 22520, 22521 as appropriate."
 
Look out: CPT doesn't always list add-on codes directly after all of their primary procedure codes. In most cases when the add-on code and primary code(s) are not listed together, CPT provides instructions on which code(s) should accompany the add-on code. For example, CPT states that you should report +63308 (Vertebral corpectomy [vertebral body resection], partial or complete, for excision of intraspinal lesion, single segment; each additional segment [list separately in addition to codes for single segment]) with 63300-63307. CPT only lists 63308 after 63307, however.

Point 3: Don't Use Modifier -51

You should never append modifier -51 (Multiple procedures) to a designated add-on code, Conklin says. Modifier -51 designates a procedure or service that can be performed independently but, in the cited case, is performed at the same time as another procedure.  
 
"Because add-on codes are defined as additional services or procedures, the -51 modifier is redundant and, for some payers, can even negatively affect your reimbursement," Conklin adds (see point 4, below).
 
CPT stresses this point by stating, "All add-on codes found in the CPT book are exempt from the multiple procedure concept."

Point 4: Don't Accept Devalued Payments

Always check your explanation of benefits carefully for claims with add-on codes to be sure the payer reimburses you the entire fee schedule rate for the billed procedures or services. Often, when a surgeon performs multiple procedures, the payer will reduce payment for the second and subsequent procedures because the presurgery evaluation, preparation and postsurgical care are already covered under the cost of the first procedure. This logic does not apply to add-on procedures, however.
 
"The fee schedule amounts assigned to add-on codes are valued to reflect their status as 'additional procedures.' Any further reduction in reimbursement below the fee schedule amount represents an unreasonable devaluation of payment," Carter says.
 
Fight reductions: If you find a payer reducing the fees for your add-on codes, be sure to appeal the claims. Cite the definition of add-on codes (explained in the "Introduction" portion of CPT) as additional procedures exempt from modifier -51 rules.